Other instalments in the winter series:
During the season, we usually heat our boats using either diesel hot-air or hot-water heating systems. However, anyone who wants to use their boat in winter too will, sooner or later, start looking for alternatives or additional options. Some are sensible, others are not. Here we show a few examples of how to keep your boat warm.
fan heater
The classic choice for quick heating when needed is the electric fan heater. It comes in many different designs and power ratings. The advantages are obvious: the appliance is inexpensive, compact, maintenance-free and can be used practically anywhere where shore power is available.
Disadvantage: Just like diesel-air heaters, electric fan heaters produce warm air that heats the room up quickly. However, the room cools down just as quickly once the appliance is switched off. Furthermore, continuous use can prove very costly. Depending on the cost of electricity at the port, energy bills can quickly mount up to a considerable amount each month. On top of that, the fan makes a noise that is at least a nuisance at night. Therefore: fan heaters are useful for quick, short-term heating, but not for continuous use.
Oil-filled radiator
Unlike fan heaters, oil-filled radiators heat the air more slowly, but are more sustainable and economical as a result. With this type of appliance, it is not the air that is heated directly, but rather oil, which then circulates within the radiator and releases heat into the room air over a sustained period. Advantage: The appliance uses less electricity, operates completely silently and is extremely safe to use. For the cabin of a 10-metre boat, for example, a 600-watt unit is more than sufficient to maintain the temperature. However, even such appliances cannot function without shore power.
Heatwaves
Heat wave heaters generate low-frequency radiation which, when it strikes objects, heats them up. The subjective sensation of warmth is pleasant and similar to that of a stove. These heaters are also very safe to use and consume less energy than, for example, a fan heater. They are available in various power ratings, ranging from a few hundred watts up to 2 or 3 kW models. These appliances also operate silently and can be installed virtually anywhere, even permanently.
Gas heater
Portable gas heaters, such as those used for camping, are practical, but are not recommended for use on a boat. The reason: Firstly, they use an open flame, and secondly, they consume the oxygen in the room. They can also lead to an increase in humidity. Although such heaters do not rely on the mains electricity supply, they should never be operated on board without supervision.
Petroleum
Like portable gas heaters, paraffin heaters also run on fossil fuel. To put it plainly: they produce exhaust fumes that make it impossible to use them in enclosed spaces such as the passenger compartment. They are suitable, at best, for heating the area under a convertible top, but must never be left unattended.
The same applies to paraffin lamps. They, too, give off heat as well as light, which can warm up small rooms. However, they are unsuitable as a substitute heating source.
Resistance wire
So-called heating cable can be used to prevent sea valves or pipes at risk of freezing from freezing over. In principle, this consists of a live cable (12 V or 230 V) which generates heat. The amount of electricity consumed depends on the length of the wire. When used as frost protection for sea valves, the energy requirement is low and the system is reliable.
Light bulb
In the past, 230-volt incandescent bulbs were also used as heaters to prevent frost in engine compartments, but this is rarely the case nowadays. The reason: conventional incandescent bulbs have all but disappeared from households and are now almost impossible to find. The principle is this: as well as light, incandescent bulbs also give off heat, which warms the surrounding air. For the engine compartment, a 60- to 100-watt bulb was often sufficient to keep the temperature above freezing. Nowadays, the same result can be achieved using electric frost protection devices, which are available from DIY stores.
Torsten Moench
Editor in Chief BOOTE